The present invention generally relates to an adhesive injection apparatus, and particularly relates to an adhesive injection apparatus to be used in an adhesive injection method which is suitable for mending cracks generated in a concrete or mortar structure.
As the method of mending cracks generated in a concrete structure, a mortar structure, or the like, such a method that an adhesive of synthetic resin such as epoxy resin, unsaturated polyester resin, or the like is injected into cracks is well known.
As the mending method using adhesive injection, formally, there was such a method (Japanese Patent No. 251791) comprising the steps of attaching pipes on cracks at suitable intervals, sealing portions except the injection nozzle attachment position, connecting the injection nozzle to an injection pump after solidification of a sealing material, and injecting an adhesive. In this method, however, there were some difficulties in work.
Recently, therefore, there are known a mending method proposed in Japanese Patent No. 1558990 in which when an adhesive is injected into cracks or the like generated in a structure, the adhesive is stored in adhesive reservoir tubes provided in desirable positions in a range from an injection nozzle to a send-out side (an injection hose) of an adhesive injector (pump) so that adhesive injection pressure acting on the cracks or the like in the structure is relieved and the stored adhesive is injected on the basis of a lasting change of the pressure of the tubes; another mending method proposed in Japanese Patent No. 1566024 in which an adhesive is filled in advance into a tube acting so as to press the adhesive filled therein, an adhesive inlet/outlet port is closed with a check valve, and then the tube is connected to an injection nozzle attached to adhesive injecting portions such as cracks or the like so that the adhesive inlet/outlet is opened and the adhesive is injected into the cracks or the like owing to a lasting change of the pressure of the tube; and so on.
As the apparatus to be used in the foregoing methods, Japanese Patent No. 1537261 proposes an adhesive injection apparatus in which one end of an adhesive reservoir tube is connected and fixed to one end of a nozzle having an injection port corresponding to cracks or the like and having, at its other end, an attachment washer, the other end of the adhesive reservoir tube is connected and fixed to another nozzle to be connected to a send-out side (hose side) of an adhesive injector (pump), and a check valve is provided on the other nozzle side. Further, Japanese Patent No. 1566024 and No. 1635377 propose an adhesive injection apparatus in which an attachment port having, at its one end, an attachment washer is connected to one end of an adhesive reservoir tube through a connection port for connection of the attachment port, and a valve system for releasing its closed state when the connection port and the attachment port are connected to each other. Moreover, Japanese Patent No. 1716183 proposes another adhesive injection apparatus.
Although these new proposals can provide an extremely remarkable effect in mending cracks in the structures, there are generated problems in the structure of the apparatuses.
In a conventional apparatus for injecting an adhesive generally, as shown in FIG. 11, an adhesive reservoir tube (hereinafter, simply referred to as a tube) 1 formed from an elastic material such as rubber or the like and a nozzle 2 are provided integrally with each other in such a manner that a flange portion 1a formed on an end of the tube 1 is interposed between a pressing portion 3a of a connection cap 3 and a flange portion 2a formed on a nozzle 2. The connection cap 3 is constituted by large and small-diameter portions 3b and 3d and the pressing portion 3a which connects the portions 3b and 3d to each other. Annular protrusions 2c and 3c are formed on the flange portion 2a of the nozzle 2 and the pressing portion 3a of the connection cap 3 respectively. The annular protrusions 2c and 3c dig into the flange portion 1a of the tube 1 so as to prevent the flange portion 1a of the tube 1 from coming-off from between the connection cap 3 and the nozzle 2. Generally, the nozzle 2 and the cap 3 are formed from synthetic resin molding.
Here, the inner diameter of the connection cap 3 is formed to be larger than the outer diameter of the flange portion 1a of the tube 1. This is because that the difference in diameter produces an air space 4 for absorbing the squeeze-out of a transformed portion of the flange portion 1a of the tube 1 due to compression when the flange portion 1a of the tube 1 is interposed between the flange portion 2a of the nozzle 2 and the pressing portion 3a of the connection cap 3 and pressed by the annular protrusions 2c and 3c.
Because of existence of such an air space 4, however, when the tube 1 is fitted into the connection cap 3, the centering of the tube 1 is not always achieved well, and there may be a case where the tube 1 is one-sidedly positioned near one-side inner wall surface of the connection cap 3 as shown in FIG. 11 (left side in the illustrated case). If the flange portion 1a of the tube 1 is compressed between the pressing portion 3a of the connection cap 3 and the flange portion 2a of the nozzle 2, the flange portion 2a is unevenly compressed so that the tube 1 is unevenly extended so as to curve as shown in FIG. 12. If the tube 1 in the curved state is directly or indirectly connected to an adhesive injector (not shown) and an adhesive is injected from the adhesive injector into the tube 1, the nozzles 2, the cap 3, and the tube 1 can not be in a linear state to cause a phenomenon that the assembly of the nozzle 2, the caps 3 and the tube 1 becomes curved, as shown in FIG. 13.
As a result, a force in the direction of coming off from the cap 3 is exerted unevenly on the tube 1 with a fear that the tube 1 actually comes off from the cap 3.